The booze is scarcely available now, despite the fact that a supply meant to last six months hit the market in September. “I don’t usually see reason to apologize,” the fighter told TMZ Sports. “But in this case I want to take this chance to apologize to absolutely everyone for our out-of-stock situation.”

According to the website, McGregor, 30, is doing his best to rectify the situation and says he is personally making sure the company is ramping up production of the popular spirit. “I was at the distillery last week and we have plans in place to be back in stock in Ireland and the United States in early December and onward,” he explained. “We are producing many hundreds of thousands of bottles now.”

Conor McGregor holds up a cup of his Notorious-branded Irish whiskey as he speaks during a news conferenceEthan Miller/Getty Images

Apparently the shortage stems from the fact that the folks at Proper No. 12 had no idea how in-demand McGregor’s Irish whiskey would be. In fact, the distillery said it “sold more cases in less than one month than many whiskey brands sell in a full year,” meaning hundreds of thousands of bottles of the triple-distilled alcoholic beverage have flown off the shelves in just a few weeks time.

The fact that fans are loving the drink seemingly has everything to do with the effort McGregor has put into making it. “I wasn’t going to sacrifice the quality of Proper No. 12 to check it off the bucket list – this project means way more to me than that,” the Dublin native told Entrepreneur in November. “I call it liquid gold.”

Fans on social media have continually praised Proper No. 12, calling the sweet and smooth drink “one of the finest whiskeys” and “Proper Holy Water.”

“I’m extremely humbled and thrilled that consumers are as excited about Proper 12 as I am,” McGregor explained to Entrepreneur. “I am lucky to have the best fans in the business, and their support and loyalty has definitely played a role in Proper 12’s success.”

What’s more? McGregor has also been generous in making sure everyone who wants a taste of Proper No. 12 can give it a try. Page Six reports the former Ultimate Fighting Championship featherweight and lightweight champ recently surprised a group of Boston firefighters with bottles of the whiskey and World Series tickets.